1. Field of the Invention
The present invention relates to a real time based system, and more particularly, to a real time based system and a method for monitoring the same in which an abnormal status of the system can be monitored in the real time environment.
2. Discussion of the Related Art
In the real time system environment, the system may cause error operation due to various factors such as unexpected operation, the outer environment, and latent bug. Such factors cause deadlock or livelock in the system, thereby failing to normally operate a set top box.
The deadlock occurs when a number of applications simultaneously use a restricted hardware resource. Once the deadlock occurs, the applications having no priority should be in a standby status for a while to obtain a desired hardware resource. The applications may be in a standby status permanently as the case may be.
The livelock occurs mainly due to program bug and means that an abnormal loop continues due to internal bug as the hardware resource is not controlled normally.
FIG. 1 illustrates an operating system (OS) and application of a general real time based system.
As shown in FIG. 1, a real time operating system (RTOS) in a real time based system operates respective application codes in order. For example, the applications 1 and 2 operate program codes by means of the RTOS and at the same time control hardware using a device driver. By contrast, an application 3 operates a program code by means of the RTOS only.
However, when a number of applications simultaneously use a restricted hardware resource, it is likely that the deadlock and the livelock occur. Although such deadlock and livelock usually occur under the general personal computer environment, they may fatally deteriorate reliability of the product under the real time environment. Therefore, it is important that the system be shortly recovered to a normal status if the deadlock and the livelock occur.